Cellular-based D2D communication is a novel technology for direct communication among multiple terminal devices which support D2D function under the control of a system. By virtue of the cellular-network-based D2D communication, system resource occupation can be reduced, the spectral efficiency of a cellular communication system can be improved, the transmission power consumption of a terminal can be lowered, and network operation expense can be lowered greatly. FIG. 1 is a diagram of a cellular-based D2D communication mode in a related art, and as shown in FIG. 1, data is transmitted between a D2D device 1 and a D2D device 2.
The D2D device needs a process to discover other adjacent D2D device(s) before performing D2D transmission. The discovery of the D2D device refers to that: the existence of a D2D device can be discovered by one or more other D2D device(s), and a characteristic such as an identity of the D2D device can be identified.
A method for discovering the D2D device in the related art is implemented as follows: the discovered D2D device broadcasts its own identity information, and one or more discovering D2D devices search for the corresponding D2D device identity information, and identify the found D2D device identity information, thereby finishing the discovery process of the D2D device.
In the discovery process of the D2D device, in order to conveniently mark and identify the identity information of the discovered device and ensure that the identity privacy of the discovered device will not be exposed, a method of encrypting the identity information of the discovered device and setting that an encryption key can be acquired by discovering device(s) selected by the discovered device only is adopted in the related art, then only the selected discovering device(s) which has known the key can identify the identity information of the discovered device when the discovered device broadcasts its encrypted identity information, and other discovering device(s) cannot acquire the privacy of the discovered device.
For the problem of higher security risk of a communication process in an identity processing process of the D2D device in the related art, there is yet no effective solution.